1. Field of the Invention
The invention relates to an apparatus and manufacturing process of carbon nanotube gate FET, for the carbon nanotube can be the channel, connector or next-level gate of transistor, and the source and drain of transistor can be exchanged and defined the specificity by outside wiring.
2. Description of the Prior Art
As entering the age of nano scale, the device is getting smaller, so fabricating the nano-scale devices using nano-scale matter becomes the trend of progress, eg. the CNT-FET bases on CNT material. But the gate width of transistor is still limited by conventional process of sputtering, metal-screen-printing and etching.
Please refer to FIG. 1, which is a schematic diagram showing the structure of carbon nanotube transistor in the prior art. First of all, depositing an oxide layer 12 above a silicon substrate 11, and the oxide layer 12 could be SiO2. Then depositing a metal thin film to be source 13a and drain 13b respectively, and patterning using the method of photolithographic etching, and coating the carbon nanotube 14 between the source 13a and drain 13b. Immersing the device into a gas where carbon is applied for the process of coating CNT on the oxide layer 12, and the conducting channel among the electrodes. Finally, depositing a gate-insulated layer 15 above source 13a, drain 13b and carbon nanotube 14, then sputtering a metal layer 16, which is the gate of device.
In the prior art of IBM who announced a 260 nm CNT-FET, but the gate of device is still the metal material mainly, eg. Al, Ti. So the size of device in this prior art is limited by the process of semiconductor.
Therefore, for decreasing the gate width, there needs to provide the CNT to replace the conventional metal gate. And the CNT can be the channel, connector or next-level gate of transistor with the specificity of metal and semiconductor.